Q41. Which blood cells are primarily involved in the production of histamine and heparin?
a) Eosinophils
b) Basophils
c) Lymphocytes
d) Neutrophils
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Correct Answer: b) Basophils
Explanation: Basophils, a type of white blood cell, are involved in the production of histamine and heparin. Histamine is important in allergic reactions and inflammation, while heparin is an anticoagulant that prevents blood clotting.
Q42. The ‘Rh factor’ in blood is:
a) A type of white blood cell
b) A plasma protein
c) An antigen found on red blood cells
d) A blood clotting factor
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Correct Answer: c) An antigen found on red blood cells
Explanation: The Rh factor, specifically the Rh D antigen, is found on the surface of red blood cells. People who have this antigen are Rh positive, and those who don’t are Rh negative. It’s important in blood transfusions and pregnancy.
Q43. Which cells in the blood are key players in creating immunity memory?
a) Monocytes
b) Platelets
c) Lymphocytes
d) Erythrocytes
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Correct Answer: c) Lymphocytes
Explanation: Lymphocytes, particularly B cells and T cells, are key in creating immune memory. After encountering an antigen, some of these cells become memory cells that remember the specific pathogen and can mount a faster response upon re-exposure.
Q44. The primary component of a blood clot is:
a) Red blood cells
b) White blood cells
c) Fibrin
d) Platelets
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Correct Answer: c) Fibrin
Explanation: The primary component of a blood clot is fibrin, a fibrous protein formed from fibrinogen during blood clotting. It creates a mesh that traps blood cells, helping to seal the wound and stop bleeding.
Q45. Which blood type is characterized by the absence of A and B antigens?
a) AB
b) A
c) B
d) O
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Correct Answer: d) O
Explanation: Blood type O is characterized by the absence of both A and B antigens on the surface of red blood cells. People with type O blood can donate to any blood group, hence it’s known as the universal donor type.
Q46. The increase in red blood cell production in response to low oxygen levels is known as:
a) Hemolysis
b) Erythropoiesis
c) Polycythemia
d) Anemia
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Correct Answer: b) Erythropoiesis
Explanation: Erythropoiesis is the process of increasing red blood cell production, especially in response to low oxygen levels in tissues. This process is stimulated by the hormone erythropoietin, primarily produced by the kidneys.
Q47. The condition where the blood lacks enough healthy red blood cells or hemoglobin is known as:
a) Leukemia
b) Anemia
c) Thrombocytopenia
d) Hemophilia
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Correct Answer: b) Anemia
Explanation: Anemia is a condition in which the blood lacks enough healthy red blood cells or hemoglobin. This leads to reduced oxygen flow to the body’s organs and can cause fatigue and other symptoms.
Q48. The main site of gas exchange in the circulatory system is the:
a) Heart
b) Arteries
c) Veins
d) Capillaries
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Correct Answer: d) Capillaries
Explanation: Capillaries are the main site of gas exchange in the circulatory system. They are small blood vessels where oxygen and nutrients are exchanged with tissues, and carbon dioxide and other waste products are collected.
Q49. Platelets are formed from larger cells in the bone marrow known as:
a) Red blood cells
b) Megakaryocytes
c) Lymphocytes
d) Myeloblasts
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Correct Answer: b) Megakaryocytes
Explanation: Platelets are small fragments of larger cells called megakaryocytes in the bone marrow. Megakaryocytes release platelets into the bloodstream, where they play a crucial role in blood clotting.
Q50. The fluid part of blood, which is composed mainly of water and in which blood cells are suspended, is called:
a) Serum
b) Plasma
c) Lymph
d) Interstitial fluid
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Correct Answer: b) Plasma
Explanation: Plasma is the fluid part of blood, composed mainly of water and containing dissolved proteins, glucose, clotting factors, electrolytes, and hormones. It is the medium in which blood cells and other components are suspended.